Multifilament synthetic yarn products

ABSTRACT

Multifilament, thermoplastic, synthetic yarn has acute angled pleats substantially in a single plane as a result of being formed into a flat pleated ribbon composed of a series of adjacent such yarns and being thereafter dissociated from said ribbon form by separating the individual yarns. The characteristics of the ribbon as an intermediate useful product are described as well as the method for making the pleated ribbon.

United States Patent Inventor Thomas T. Constantine South Easton, Mass.

Appl. No. 799,684

Filed Feb. 17, 1969 Patented Apr. 13, 1971 Assignee Fabric Research Laboratories, Inc.

Dedham, Mass.

MULTIFILAMENT SYNTHETIC YARN PRODUCTS 4 Claims, 8 Drawing Figs.

US. Cl. 57/140,

28/72.l4 Int. Cl D02g 3/24 Field of Search 28/72. 14, l,

[56] References Cited UNITED STATES PATENTS 2,146,694 2/1939 Wrigley et al 26/ l 8.6 2,263,712 ll/194l Wrigley et al 26/l8.6 2,368,637 2/1945 Bruenner et al. 28/1.6X 3,287,784 11/1966 Loftin et al. 28/1 Primary ExaminerLouis K. Rimrodt Attorney-Rowland V. Patrick ABSTRACT: Multifilament, thermoplastic, synthetic yarn has acute angled pleats substantially in a single plane as a result of being formed into a flat pleated ribbon composed of a series of adjacent such yarns and being thereafter dissociated from said ribbon form by separating the individual yarns. The characteristics of the ribbon as an intermediate useful product are described as well as the method for making the pleated ribbon.

Patented April 13, 1971 3,574,991

5 Sheets-Sheet 2 Patented April 13, 1971 5 Sheets-Sheet 5 Patented April 13, 1971 3,574,991

5 Sheets-Sheet 4 Patented April 13, 1971 5 Sheets-Sheet 5 FIG.60

l MULTIFILAIVIENT SYNTHETIC YARN PRODUCTS This invention relates to bulking synthetic thermoplastic multifilament yarns and more particularly deals with improving the symmetry of crimp formation in quantity production of such yarns, as well as providing simultaneously a process which lends itself to large scale production rates and produces a novelintermediate that has utility as a fabric.

Mechanical synthetic yarn crimping as presently commercially practiced includes stuffer box, knife edge, gear crimping, false twisting, knit-unknit, etc. Stuffer box crimping has a characteristic random location of crimps in that the bends are never always in the same plane, but can be in any of an infinite number of planes and their apices or elbows are spaced, within limits, at various unordered distancesalong the strand. Knife edge crimping is characterized by the formation of coils whose pitch reverses at various increments of distance along the strand. The random or changing geometry of the crimps imparted by these processes is bound to cause subsequent dye absorption variations in theyarn or texture variation in articles woven, knitted, tufted 'or otherwise fabricated therewith.

Gear crimping more nearly succeeds in uniformity of crimp but production is relatively slow and damage to the strands by way of loss in tensile strength is inevitable. Similarly, both untwisting and unraveling is slow and hence costly particularly because each yarn has to be dealt with individually. Additionally false twisting does not lend itself to use with anything but relatively'fine denier yam.

Apparatus as described in Walton U. S. Pat. No. 2,765,514 has also been used to treat yarns, as well as fabrics, to collapse l the yarn longitudinally and in the case of multifilament yarn, to increase its diameter by the formation of crimps of random geometry in the individual filaments. I It has now been discovered that in a Walton type operation the geometrical symmetry and uniformity of configuration change imparted to therrnosplastic yarns is startlingly rendered more ordered when separately twisted yarns are multiply processed together in contacting side-by-side monolayer relation. When a side-by-side feed is utilized the yarns can be bodily pleated into zigzag dovetailing configuration with substantially all the pleats lying in the plane of the monolayer of yarns forming a web or ribbon of yarns. The two edge yams, however, take on the pleated configuration only on their inside portions, i.e., that part of the edge yarn which lies against its neighboring yarn, the remainder of the edge yarns being unpleated and having merely those characteristics that an entire yarn has when subjected to the same operation singly, i.e., not in side-by-side contact with any other yarn.

The importance of embracing each yarn on each side during the operation is evidenced by the fact that noticeably different effects are produced in the two outside edge yarns of the composite monolayer whose outer sides are not so embraced by any adjacent yarns. These different and poorer efi'ects with respect to the outside edge yarns render it desirable to detach and discard or set aside these yarns as lower grade, their configurations being inferior to those of the completely bodily pleated intermediate yarns.

By proper adjustment of the speed ratio of the surfaces moving at differential speeds, the adjacent intermediate yarns emerge from the operation so longitudinally collapsed as to be in what can be referred to as a jammed state with the legs of the pleats running more nearly crosswise of the ribbon than parallel to its length due to the angles of the elbows of the pleats being acute angles, This superposes on the uniform bodily pleating in all the intermediate yarns a bulking of the yams in directions out of the plane of the monolayer increasing the yarn cross-sectional area and hence increasing the thickness of the web or ribbon. Increase in average thickness is by a factor of as high, in some cases, as 4. This bulking is accompanied by a geometrical change in the crosssectional area of the composite multifilament yarns from their original circular or nearly circular cross sections towards rectilinear shape sometimes with even greater height than width. A pleated yarn of rectilinear cross section gives novel textured effects.

The self-sustaining integrity of the ribbon form of the monolayer of yams as it emerges from the apparatus is also fortified, on one surface only, by an interentanglement of individual filaments in adjacent multifilament yarns as a result of the scuffing action of the slower moving surface in retarding the speed of advance of the sheet of monolayer yarns. Upon separation of the yarns, no detrimental effect resulting from this entanglement is discernible.

The characteristics of the product of this invention are shown in the accompanying photomicrographs which are submitted in lieu of inked drawings since the latter would not adequately depict these characteristics, accompanied by an inked drawing showing one feature of the invention FIG. I is a magnified (3x) view of a self-sustaining multiyam textile ribbon of the invention which is an intermediate in the production of individual bulked yarns;

FIG. 2 is a still further magnified view of a section of the ribbon of FIG. I with one side yarn thereof in the act of being mechanically separated from the adjoining portion of the ribbon;

FIG. 3 is a still further magnified view (20x) of one surface of a ribbon similar to that shown in FIG. 1; but with the longitudinal axis of the ribbon of the yarns extending horizontally instead of vertically as in FIGS. 1 and 2;

FIG. 4 is a similar view of the opposite surface of the ribbon shown in FIG. 3 at the same magnification;

FIG. 5 is a perspective view photomicrograph of a single yarn separated from the ribbon of FIG. 1;

FIGS. 6 a and 6 b are photomicrographs respectively of a yarn before treatment in accordance with this invention and after treatment in accordance with this invention producing the novel crimped yarn shown in FIG. 6 b;

FIG. 7 illustrates a construction having the structure of the invention incorporated periodically along the length of a series of continuous filament yarns.

The textile web shown in FIG. 1 was made by feeding ten ends of 3,200-200 polypropylene yarn from a creel through a 10 per inch reed to a 24 inch width compacting machine of the type shown and described in US. Pat. No. 2,765,514 in such manner that the individual yarns having 0.5 twists per inch were fed in close contacting side-by-side juxtaposition and in a monolayer, with the upper roll of the machine operating at a surface speed of 27 feet per minute and the lower roughened retarding roll at 5.5 feet per minute.

The single yarn thickness was .015 inch and the yarns were compressed, by means of this operation, to one quarter of their original length when the blade wa, set at 0.180 inches from the narrowest portion of the nip oi a 6 inch diameter roll machine.

After the yarns emerged from the compacting machine, they were separated from one another by passing them through another reed and then were wound in straightened configuration onto suitable tubes with the two edge yarns being discarded.

The configuration of the ribbon prior to the separation of the yarns is shown in FIG. 1. As there shown, the individuality of the yarns has been substantially obliterated by the jammed dovetail interlocking of the zigzag pleating with the angle of the bends being sharp and acute and all extending in the same side-to-side direction, i.e., all lying flatly in the plane of the web.

The edges of the ribbon are less regularly configured due to the fact that they were not confined on their outside edges during the operation.

That the individuality of the yarns was not destroyed is illustrated by FIG. 2 where the portion of the ribbon on the right side of the break 10 is one of the outside side edge yarns which when separated leaves the edge of the adjoining portion in a scalloped regular symmetrical configuration.

The boundary between that remaining yarn and its neighbor is revealed by the slight separation shown at 12.

FIG. 3 is illustrative of the jammed configuration of the ribbon on the surface which was adjacent the faster roll during the pleating operation.

FIG. 4 demonstrates the slightly scuffed nature of the surface which passed through the nip against the slower operating roll resulting in some entanglement of filaments of one yarn with those of an adjacent yarn, for example at 16, and operating to augment the integrity of the ribbon form of the monolayer of yarns. This is particularly beneficial where it is contemplated that the web will be used intact without separation of the yarns. Typical such uses include use as gasketing or packing material with or without infiltration with resins, lubricants or graphite materials, as the wear surface in a needled carpet or as a reinforcing ply for plastic or other laminates.

FIG. 5 shows the manner in which a yarn subjected to the above operation increases in thickness and takes on a rectilinear cross-sectional configuration of the yarn. Such reshaping of the cross section of the yarn is caused by the forced jamming the yarns into the confined passageway into greater contacting side-by-side relation.

FIG. 6 b shows in a individual separated yarn how the crimps in the individual filaments of the multifilament yarn lie substantially uniformly with respect to a single plane and do not, as in stuffer box crimped yarns, extend in random planes.

When the yarns are separated and then each yarn wound in a straightened condition on a tube, it will be found that a permanent set has been imparted to the yarn, i.e., when the yarn is removed from the tube and either allowed to relax or subsequently subjected to steam or other heat, the yarn will tend to return to its pleated configuration, all as a result of a single pass through the compressive shrinking machine. Subsequent tension followed by relaxation will dephase the pleats and bulk the yarn.

This indicates that the heat generated in the operation on thermoplastic synthetic yarns is sufficient, without later supplemental heat treatment to relieve stresses imparted to the filaments by the bending. This enhances the permanency of the pleats.

It is further contemplated, as shown in ElG. 7, that the operation may be performed spacially along lengths of yarn by intermittently separating the rolls or retracting the blade for fractions of a second or longer. In FIG. 7 ,20 is pleated area and 22 is unpleated area. This can provide novel yarn effects which are not achievable in stuffer box crimping.

-While the fabric and yarn shown in the drawings were made on a Walton-type machine, it is contemplated that the products claimed herein and the methods for their productions may be practiced on other moving surface confined passageway compressor shrinkage machinery. The word ribbon" as herein above used and as used in the appended claims is not intended to imply any limitation as to width, as the width is governed solely by the economics of mechanical crimping machine width.

lclaim:

l. A self-sustaining flat textile ribbon comprising a monolayer of multifilament thermoplastic synthetic yarns interlocked with each other along their lengths by longitudinally jammed dovetailing acute-angled pleats lying substantially in the plane of the ribbon, said yarns in the portions between the bends of the pleats exhibiting generally rectilinear composite filament cross sections.

2. A self-sustaining flat textile ribbon as claimed in claim 1 wherein said ribbon exhibits on one surface thereof an interentanglement of filaments of adjacent yarns to a degree not present on the other surface of the ribbon.

3. A self-sustaining flat textile ribbon as claimed in claim 1 having, in addition, a pair of edge yarns presenting random crimps along their outside edges but being interlocked with the pleats of adjacent yarns.

4. Continuous lengths of multifilament thermoplastic synthetic yarns interlocked together to form the structure of the ribbon claimed in claim 1 intermittently along their lengths. 

2. A self-sustaining flat textile ribbon as claimed in claim 1 wherein said ribbon exhibits on one surface thereof an interentanglement of filaments of adjacent yarns to a degree not present on the other surface of the ribbon.
 3. A self-sustaining flat textile ribbon as claimed in claim 1 having, in addition, a pair of edge yarns presenting random crimps along their outside edges but being interlocked with the pleats of adjacent yarns.
 4. Continuous lengths of multifilament thermoplastic synthetic yarns interlocked together to form the structure of the ribbon claimed in claim 1 intermittently along their lengths. 